Device for cleaning surrounding air fed to passenger compartment of motor vehicle

ABSTRACT

Various types of air cleaning devices for cleaning air fed to a passenger compartment of a motor vehicle are described. These air cleaning devices are arranged to incorporate with a cowl top structure of the vehicle. In one type, an air filter is disposed in an external air introduction passage led to the passenger compartment, and when the air filter is blocked with arrested dusts, a bypass passage is established to keep the feeding of atmospheric air to the passenger compartment. In a modified type, the bypass passage is instantly blocked and an internal air circulation mode is established. In one type, an electrostatic air collecting unit is used for arresting very fine particles in the atmospheric air fed to the passenger compartment. In order to achieve a smoothed air flow in the electrostatic air collecting unit, smoothly curved air guide passages are defined between positive and negative electrode plates. In one type, two hood ridge reinforcing hollowed structures are used for feeding the air box and thus the passenger compartment with a satisfied amount of atmospheric air. In order to facilitate the maintenance of the air filter in the air box, an inspection aperture is provided in the cowl top. Usually, the inspection aperture is covered by a lid.

This application is a divisional application of the parent applicationSer. No. 08/113,639, filed Aug. 31, 1993, which is now U.S. Pat. No.5,368,620.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to air cleaning devices for usein a motor vehicle, and more particularly to air cleaning devices of atype which cleans the surrounding air fed to a passenger compartment ofthe motor vehicle from the outside of the vehicle.

2. Description of the Prior Art

In order to clarify the task of the present invention, one conventionalair cleaning device of the above-mentioned type will be described withreference to FIG. 29 of the accompanying drawings.

In FIG. 29 , the conventional air cleaning device is shown, which ismounted in a front part of a motor vehicle. That is, the air cleaningdevice comprises generally an air box 1 which is mounted beneath a cowltop 2 of the vehicle. The cowl top 2 is formed with an air intakeopening 3 through which the atmospheric air is introduced into the airbox 1. Within the air box 1, there is installed a cowl duct 5 throughwhich the interior of the air box 1 is connected with an air intake case4. Although not shown in the drawing, the air intake case 4 is led to apassenger compartment of the vehicle through suitable guide ducts. Anair filter element 6 constructed of pleated paper is disposed on thecowl duct 5 and an electric air blower 7 is mounted in the air intakecase 4. Upon energization of the air blower 7, the atmospheric air inthe air box 1 is forced to pass through the air filter 6 and the airthus cleaned is led to the passenger compartment through the guideducts.

However, due to its inherent construction, the above-mentioned aircleaning device has the following drawbacks and weak points.

First, when the air filter 6 becomes severely blocked or clogged witharrested dust due to long use or the like, the amount of fresh air fedto the passenger compartment is considerably reduced. In particular, inwinter, a temporary blocking of the air filter 6 tends to occur due tofreezing of moisture in the filter 6. In this case, the passengercompartment is given substantially no fresh air through the air cleaningdevice. Furthermore, a marked load is applied to the electric air blower7.

Second, due to the nature of the pleated paper by which the air filter 6is made, the conventional air cleaning device exhibits a marked air flowresistance. Furthermore, the shape of air flow passage defined in thedevice is given little thought, which promotes the marked air flowresistance of the device. These induce that high power and thusexpensive air blower 7 is necessary for feeding the passengercompartment with a satisfied amount of clean air.

Third, it is very difficult to check and change the air filter element6. In fact, in the conventional device, for such maintenance, it isnecessary to dismantle the entire of the cowl top 2 from the vehiclebody.

Fourth, due to the nature of the pleated paper by which the air filter 6is made, the filter 6 fails to catch very fine particles.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide varioustypes of air cleaning devices for use in a motor vehicle, which cansolve the above-mentioned drawbacks.

According to a first aspect of the present invention, there is providedan air cleaning device for use in a motor vehicle having a cowl top anda passenger compartment. The air cleaning device comprises a firststructure secured to the cowl top to constitute an air box; a secondstructure secured to the first structure to constitute an air intakecase; first means for defining in the cowl top a first opening throughwhich the interior of the air box and the surrounding air arecommunicated; second means for defining a second opening through whichthe interior of the air box and that of the air intake case arecommunicated; third means for fluidly communicating the interior of theair intake case with the passenger compartment; an air filter holderdisposed in the air box at a position above the second opening; an airfilter element disposed on the air filter holder; an electric air blowerdisposed in the air intake case for, upon energization thereof,generating air flow from the first opening to the passenger compartmentthrough the interior of the air box, the air filter element, the secondopening, the interior of the air intake case and the third means; andbypass means for producing a bypass passage between the interior of theair box and that of the air intake case bypassing the air filter elementwhen the air filter element is blocked with arrested dusts by a certaindegree.

According to a second aspect of the present invention, there is providedan air cleaning device for use in a motor vehicle having a cowl top anda passenger compartment. The air cleaning device comprises a firststructure secured to the cowl top to constitute an air box; a secondstructure secured to the first structure to constitute an air intakecase; first means for defining in the cowl top a first opening throughwhich the interior of the air box and the surrounding air arecommunicated; second means for defining a second opening through whichthe interior of the air box and that of the intake case arecommunicated; third means for fluidly communicating the interior of theair intake case with the passenger compartment; a duct installed in theair box, the duct having a mouth portion directed toward the firstopening and a tail portion connected with the second opening; anelectrostatic dust collecting unit installed in the mouth portion of theduct; an electric air blower disposed in the air intake case for, uponenergization, generating air flow from the first opening to thepassenger compartment through the interior of the air box, theelectrostatic dust collecting unit, the duct, the second opening, theinterior of the air intake case and the third means; means for definingin the air intake case a third opening; passage means for communicatingthe third opening with the passenger compartment; a switch doorpivotally connected to the air intake case to selectively open and closethe third opening and the second opening; an electric actuator fordriving the switch door; and control means which, when an excessiveamount of dusts is collected by the electrostatic dust collecting unit,stops the operation of the electrostatic dust collecting unit and at thesame time energizes the electric actuator to pivot the switch door toclose the second opening and open the third opening.

According to a third aspect of the present invention, there is providedan air cleaning device for use in a motor vehicle having a cowl top anda passenger compartment. The air cleaning device comprises a firststructure secured to the cowl top to constitute an air box; a secondstructure secured to the first structure to constitute an air intakecase; first means for defining a first opening through which theinterior of the air box and that of the air intake case arecommunicated; second means for fluidly communicating the interior of theair intake case with the passenger compartment; an air filter holderdisposed in the air box at a position above the second opening; an airfilter element disposed on the air filter holder; an electric air blowerdisposed in the air intake case for, upon energization thereof,generating air flow from the interior of the air box to the passengercompartment through the air filter element, the first opening, theinterior of the air intake case and the second means; a hood ridgereinforcing structure which extends along a side wall of an engine roomof the motor vehicle, the hood ridge reinforcing structure having acommunication opening exposed to the interior of the air box; and thirdmeans for defining in the hood ridge reinforcing structures an airintake opening which is exposed to the surrounding air.

According to a fourth aspect of the present invention, there is providedan air cleaning device for use in a motor vehicle having a cowl top anda passenger compartment. The air cleaning device comprises a firststructure secured to the cowl top to constitute an air box; a secondstructure secured to the first structure to constitute an air intakecase; first means for defining a first opening through which theinterior of aid air box and that of the air intake case arecommunicated; second means for fluidly communicating the interior of theair intake case with the passenger compartment; a hood ridge reinforcingstructure which extends along a side wall of an engine room of the motorvehicle, the hood ridge reinforcing structure having a communicationopening exposed to the interior of the air box; third means for definingin the hood ridge reinforcing structure an air intake opening which isexposed to the surrounding air; an elongate casing having two inletopenings exposed to the interior of the air box and one air outletopening connected to the first opening; an electrostatic dust collectingunit installed in the elongate casing; a charcoal filter installed in anair passage positioned downstream of the air outlet opening of theelongate casing; an electric air blower installed in the air intake casefor, upon energization thereof, generating air flow from the air intakeopening of the hood ridge reinforcing structure to the passengercompartment through the interior of the hood ridge reinforcingstructure, the communication opening of the hood ridge reinforcingstructure, the interior of the air box, each of the air inlet openingsof the elongate casing, the interior of the electrostatic air collectingunit, the charcoal filter and the interior of the air intake case.

According to a fifth aspect of the present invention, there is providedan air cleaning device for use in a motor vehicle having a passengercompartment. The air cleaning device comprises a cowl top structureincluding a cowl top panel which extends transversely at a rear portionof an engine room of the vehicle, the cowl top panel including atransversely extending front part which faces the engine room and atransversely extending upper part which faces upward; a transverselyextending dash upper panel secured to the cowl top panel to constitutean air box; an intake air case connected to the air box; means forfluidly communicating the interior of the intake air case with thepassenger compartment; means for defining an air inlet opening throughwhich the surrounding air and the interior of the air box arecommunicated; means for defining a first opening through which theinterior of the air box and that of the intake air case arecommunicated; means for defining a second opening in the transverselyextending upper part of the cowl top panel; a cowl top cover secured tothe transversely extending upper part to cover the first opening; meansfor defining a third opening in the cowl top cover, so that the interiorof the air box is viewed from the outside through the second and thirdopenings; a lid detachably connected to the cowls top cover in a mannerto cover the third opening; an air filter holder disposed in the air boxat a position just above the first opening; an air filter elementdisposed on the air filter holder; and an electric air blower disposedin the air intake case for, upon energization thereof, generating airflow from the air inlet opening to the passenger compartment through theinterior of the air box. The air filter element, the first opening, theinterior of the air intake case and the means for communicating theinterior of the air intake case with the passenger compartment.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the present invention will becomeapparent from the following description when taken in conjunction withthe accompanying drawings, in which:

FIG. 1 is a sectional view of an air cleaning device for use in a motorvehicle, which is a first embodiment of the present invention;

FIG. 2 is a perceptive view of an air filter holder and a pleated paperfilter mounted thereon, which are employed in the first embodiment;

FIG. 3 is a view of a damper door structure for producing a bypasspassage, which is used in the first embodiment;

FIG. 4 is a view similar to FIG. 1, but showing a second embodiment;

FIG. 5 is a perspective view of some parts used in the secondembodiment;

FIG. 6 is a view similar to FIG. 1, but showing a third embodiment;

FIG. 7 is an electric circuit employed in the third embodiment;

FIG. 8 is a view similar to FIG. 1, but showing a fourth embodiment ofthe present invention;

FIG. 9 is an electric circuit employed in the fourth embodiment;

FIG. 10 is a transversely sectioned view of an electrostatic dustcollecting unit employed in a fifth embodiment of the present invention;

FIG. 11 is a sectioned view of the electrostatic dust collecting unittaken along the line XI--XI of FIG. 10;

FIG. 12 is a sectioned view of the electrostatic dust collecting nittaken along the line XII--XII of FIG. 10;

FIG. 13 is a view similar to FIG. 11, but showing an electrostatic dustcollecting unit employed in a sixth embodiment;

FIG. 14 is a transversely sectioned view of an electrostatic dustcollecting unit employed in a seventh embodiment of the presentinvention;

FIG. 15 is a view similar to FIG. 14, but showing an electrostatic dustcollecting unit employed in an eighth embodiment;

FIG. 16 is a schematically illustrated front view of a motor vehicle,showing a cowl top structure and two hood ridge reinforcing hollowedstructures which are employed in a ninth embodiment of the presentinvention;

FIG. 17 is a sectional view similar to FIG. 1, but showing the ninthembodiment;

FIG. 18 is a sectional view of a portion of the vehicle where a frontleft tire is positioned;

FIG. 19 is a view similar to FIG. 16, but showing a cowl top structureand two hood ridge reinforcing hollowed structures which are employed ina tenth embodiment of the present invention;

FIG. 20 is a perspective view of an additional water drain openingemployed in the tenth embodiment;

FIG. 21 is a sectional view similar to FIG. 1, but showing the tenthembodiment;

FIG. 22 is a view similar to FIG. 16, but showing a cowl top structureand two hood ridge reinforcing hollowed structures which are employed inan eleventh embodiment of the present invention;

FIG. 23 is a sectional view similar to FIG. 1, but showing the eleventhembodiment;

FIG. 24 is a schematically illustrated front view of a motor vehicleshowing a cowl top structure which is employed in a twelfth embodimentof the present invention;

FIG. 25 is a sectional view of a cowl top structure of the vehicle,showing various parts employed in the twelfth embodiment;

FIG. 26 is a perspective view of a cowl top cover and a lid which areemployed in the twelfth embodiment;

FIGS. 27 and 28 are sectional views showing the methods for detachablyconnecting the lid to the cowl top cover; and

FIG. 29 is a view similar to FIG. 1, but showing a conventional aircleaning device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 to 3 of the accompanying drawings, there is shown afirst embodiment of the present invention.

As is seen from FIG. 1, the air cleaning device 100 of this firstembodiment comprises an air box 1 which is mounted beneath a cowl top 2of a motor vehicle. The cowl top 2 is formed with an air intake opening3 through which the atmospheric air is introduced into the air box 1.

Within the air box 1, there is installed an air filter holder 12. Theair filter holder 12 has an inclined open upper side on which a pleatedpaper filter 6 (see FIG. 2) is mounted and an open lower side 14 whichis mounted on a cowl duct 5 projected into the air box 1. The cowl duct5 has a downstream part to which an air intake case 4 is integrallyconnected. As is seen from FIG. 1, the air intake case 4 is led to apassenger compartment "P" of the motor vehicle through suitable airguide ducts "D". An electric air blower 7 is installed in the air intakecase 4.

As is seen from FIG. 2, one side wall of the air filter holder 12 isformed with a triangular opening 11 through which the interior of thefilter holder 12 is communicated with the exterior of the same.

As is seen from FIG. 3, a triangular damper door 13 is pivotallyconnected through a pivot pin 17 to an inner wall of the filter holder12 in a manner to selectively open and close the triangular opening 11.A spring 18 is connected to the damper door 13 to bias the same in adirection to close the triangular opening 11. The arrangement betweenthe damper door 13, the pivot pin 17 and the spring 18 may be understoodfrom FIG. 5.

In the following, operation of the first embodiment 100 will bedescribed.

Upon energization of the electric air blower 7, the atmospheric air isforced to enter the air box 1 through the air intake opening 3 of thecowl top 2, pass through the pleated paper filter 6 and then enter thepassenger compartment P through the air guide ducts D. Due to provisionof the paper filter 6, the passenger compartment P is given fresh,cleaned or filtered atmospheric air.

While, when, due to long use or the like, the pleated paper filter 6becomes severely blocked with arrested dust or the frozen moisture inwinter, the negative pressure created downstream of the filter 6 becomesmarked. Thus, when the negative pressure increases to a certain degreewhich overcomes the biasing force produced by the spring 18, the damperdoor 13 is forced to open the triangular opening 11 of the air filterholder 12. In this condition, the atmospheric air is led into the airintake case 4 through the triangular opening 11 bypassing the blockedpaper filter 6. That is, the passenger compartment P is given fresh (butnot-filtered) atmospheric air.

Referring to FIGS. 4 and 5, there is shown a second embodiment of thepresent invention, which is a slight modification of the firstembodiment.

Since the air cleaning device 200 of the second embodiment is similar inconstruction to the air cleaning device 100 of the above-mentioned firstembodiment, only parts and constructions which are different from thoseof the first embodiment will be described in the following forfacilitation of description.

As is seen from FIG. 4, in the second embodiment, the air intake case 4is formed with an internal air intake opening 15, and a switch door 16is pivotally connected to the cowl duct 5 in a manner to selectivelyopen and close the open lower side 14 of the air filter holder 12 andthe internal air intake opening 15. The internal air intake opening 15is communicated with the passenger compartment P through a duct D', anda known electric actuator (not shown) is arranged to drive the switchdoor 16.

As is understood from FIG. 5, a switch 20 is installed in the air filterholder 12. The switch 20 takes OFF (or open) condition when thetriangular damper door 13 closes the triangular opening 11 and ON (orclosed) condition when the damper door 13 opens the opening 11. That is,the switch 20 has a sensor lever 20a against which the damper door 13abuts to close the switch 20 when swung inward due to creation of thenegative pressure in the air filter holder 12.

Designated by numeral 19 in FIG. 5 is a cam member which is incorporatedwith one end portion of the spring 18 for providing the damper door 13with a so-called detent feeling movement. That is, due to slidingengagement between the end portion of the spring 18 and a raised part ofthe cam member 19, the damper door 13 can keep its closed position (asshown by solid line in the drawing) just before the negative pressure inthe filter casing 12 increases to the given degree. Furthermore, thedamper door 13 can keep its open position (as shown by phantom line inthe drawing) just before the negative pressure reduces to the givendegree.

In the following, operation of the second embodiment 200 will bedescribed.

Usually, the switch door 16 closes the internal air intake opening 15.Thus, upon energization of the air blower 7, the passenger compartmentis given fresh, cleaned or filtered atmospheric air, like in the case ofthe above-mentioned first embodiment.

While, when, due to long use or the like, the pleated paper filter 6becomes severely blocked or clogged with arrested dust or the frozenmoisture in winter, the negative pressure created in the air filterholder 12 becomes marked. Thus, when the negative pressure increases toa certain degree which overcomes the biasing force of the spring 18, thedamper door 13 is forced to open permitting the end portion of thespring 18 (see FIG. 5) to ride over the raised part of the cam member19. Thus, for a moment, the atmospheric air is led into the passengercompartment P through the triangular opening 11 bypassing the blockedpaper filter 6. When the damper door 13 thus takes the open position,the switch 20 is turned ON. Upon this, the electric actuator (not shown)for the switch door 16 pivots the same to open the internal air intakeopening 15 and close the open lower side 14 of the air filter holder 12.Under this condition, atmospheric air is not led into the passengercompartment and only the air in the passenger compartment is forced tocirculate therein through the internal air intake opening 15. That is,when the pleated paper filter 6 is severely blocked by arrested dusts,the air cleaning device 200 changes its mode to an internal aircirculation mode automatically. Thus, the electric air blower 7 isprotected from a marked load.

Referring to FIGS. 6 and 7, there is shown a third embodiment of thepresent invention, which is a modification of the second embodiment.

Since the air cleaning device 300 of the third embodiment is similar inconstruction to the air cleaning device 200 of the above-mentionedsecond embodiment, only parts and constructions which are different fromthose of the second embodiment will be described in the following.

As is seen from FIG. 6, in the third embodiment, the air intake case 4is further formed with an air outlet port 21 to which an air inlet duct23 of an air cooling unit 22 is connected. An air outlet duct (nonumeral) from the air cooling unit 22 leads to demister nozzles (notshown) which face a windshield of the vehicle.

As shown in FIG. 7, the air cooling unit 22 comprises an evaporator 25for cooling air. Designated by numeral 24 is the actuator for the switchdoor 16.

When the switch door 16 closes the open lower side 14 of the air filterholder 12 causing the air cleaning device 300 to assume the internal aircirculation mode, the evaporator 25 is operated to cool and thusdehumidify the air which is fed to the windshield from the air intakecase 4. Thus, the windshield can be demisted.

Referring to FIGS. 8 and 9, there is shown a fourth embodiment of thepresent invention.

As is seen from FIG. 8, the air cleaning device 400 of this fourthembodiment comprises an air box 1 which is mounted beneath a cowl top 2of a motor vehicle. The cowl top 2 is formed with an air intake opening3 through which the atmospheric air is introduced into the air box 1.

Within the air box 1, there is installed a duct 405. As shown, the duct405 has a curved base portion (no numeral) mounted on a holder 406 fixedto the air box 1. The duct 405 has a mouth portion directed upstreamtoward the air intake opening 3 of the cowl top 2. An air intake case 4is connected to the air box 1 through the holder 406. Within the airintake case 4, there is installed an electric air blower 7. Designatedby numeral 411 is a switch door which corresponds to the switch door 16of the afore-mentioned second and third embodiments. That is, the airintake case 4 is formed with an internal air intake opening 430 which isconnected through air guide ducts D' to suitable portions of thepassenger compartment P. The switch door 411 is pivotally moved betweenan external air induction position wherein, as shown, the internal airintake opening 430 is closed and a passage from the duct 405 to the airblower 7 is opened and an internal air circulation position wherein theinternal air intake opening 430 is opened and the passage is closed.Denoted by numeral 422 is an electric actuator for driving the switchdoor 411.

An air passage 432 extends from the air intake case 4 to an air coolingunit 434 of an air conditioner of the vehicle. Outlet ducts 436 extendfrom the air cooling unit 434 to various portions of the passengercompartment P. As will be described hereinafter, the air cooling unit434 comprises an evaporator 425 (see FIG. 9) and a relay 424 controlledby a control circuit 421.

Within the mouth portion of the duct 405, there is installed anelectrostatic dust collecting unit 409. The unit 409 comprises generallya dust ionizing part 406 and a dust collecting part 408. The dustcollecting part 408 comprises a plurality of positive electrode plates407a and a plurality of negative electrode plates 407b. These positiveand negative electrode plates 407a and 407b are arranged alternatelydefining certain clearances therebetween.

Thus, when, with the switch door 411 closing the internal air inletopening 430, both the air blower 7 and the electrostatic dust collectingunit 409 are energized, the atmospheric air is led to the passengercompartment P through the air intake opening 3, the dust collecting unit409 and the air guide ducts (not shown). During traveling in the duct405, air dusts (viz., fine particles in air) are collected in theclearances between the positive and negative electrode plates 407a and407b. Thus, the passenger compartment P is given fresh, cleaned ordust-free atmospheric air.

In FIG. 9, there is shown an electric circuit for the air cleaningdevice 400 of the fourth embodiment. Denoted by numeral 414 is a DCpower source, 412 is a manual switch which is connected to the powersource 414, 413 is a relay which is connected to the manual switch 412,415 is a high tension generator which is connected to the relay 413, 416is a malfunction detecting circuit which is connected to the relay 413,the high tension generator 415, the manual switch 412 and the positiveelectrode plates 407a and 417 is a malfunction alarm bulb which isconnected to the malfunction detecting circuit 416.

Designated by numeral 421 is a control circuit for controlling both theelectric actuator 422 of the switch door 411 and the air cooling unit434 of the air conditioner. The control circuit 421 receives informationsignals from the malfunction detecting circuit 416. The electricactuator 422 and the air cooling unit 434 are powered by anotherelectric power source 414'.

In the following, operation of the fourth embodiment 400 of theinvention will be described.

For ease of understanding, the description will be commenced withrespect to an external air introduction mode of the air cleaning device400.

Under this condition, the air blower 7 and the dust collecting unit 409are energized and the switch door 411 assumes the external air inductionposition as shown in FIG. 8. Thus, as has been described hereinabove,the passenger compartment P of the vehicle is given fresh, cleaned ordust-free atmospheric air. Of course, when the air cooling unit 434 ofthe air conditioner is kept energized, part of the fresh air fed to theair cleaning device 400 is cooled for conditioning the air in thepassenger compartment P.

When, due to long use or the like of the air cleaning device 400, anexcessive amount of dusts (or fine particles) is collected in theclearances between the positive and negative electrode plates 407a and407b of the dust collecting unit 409, the malfunction detecting circuit416 stops energization of the dust collecting unit 409 and at the sametime energizes the malfunction alarm bulb 417 to let the operator (ordriver) know the malfunction of the dust collecting unit 409. In fact,when excessive amount of dusts are collected in such clearances, anelectric leakage tends to occur, which allows the operation of themalfunction detecting circuit 416.

Upon receiving an information signal representing the malfunction of theair collecting unit 409, the control circuit 421 energizes the actuator422 to pivot the switch door 411 to the internal air circulationposition wherein the internal air intake opening 430 is opened and thepassage from the duct 405 to the air blower 7 is closed. Thus,thereafter, the external air is not introduced into the passengercompartment P any longer. That is, only the air in the passengercompartment P is forced to circulate therein through the internal airintake opening 430. Of course, when the air cooling unit 434 of the airconditioner is kept energized, the air is cooled for air conditioning inthe passenger compartment P.

In this fourth embodiment, the electrostatic dust collecting unit 409 isemployed. Thus, the air flow resistance of the air cleaning device 400is very small as compared with the air cleaning device which employs apleated paper filter.

As is described hereinabove, when, in the fourth embodiment, anexcessive amount of dusts is collected by the air cleaning device 400,energization of the dust collecting unit 409 is stopped and at the sametime the switch door 411 is pivoted to the internal air circulationposition shutting off the external air induction passage. That is, underthis condition, there is no air flow in the duct 405, more specifically,in the clearances in which the dusts are collected. Thus, it does notoccur that the excessive amount of dusts collected by the air collectingunit 409 is removed therefrom and carried into the passenger compartmentP.

Referring to FIGS. 10 to 12, there is shown an electrostatic dustcollecting unit 509 which is employed in a fifth embodiment 500 of thepresent invention. The fifth embodiment 500 is a modification of theabove-mentioned fourth embodiment 400.

That is, the fifth embodiment 500 has substantially the sameconstruction as the fourth embodiment 400 of FIG. 8 except for theelectrostatic dust collecting unit 409.

Thus, in the following, only the electrostatic dust collecting unit 509employed in the fifth embodiment 500 will be described with reference toFIGS. 10 to 12 for facilitation of description.

As is seen from these drawings, the electrostatic dust collecting unit509 comprises an elongate casing 501 constructed of electricallyinsulating material. The casing 501 has an air inlet portion 502 whichis to be directed toward the air inlet opening 3 (see FIG. 8) of thecowl top 2 and an air outlet portion 503 which is to be directed towardthe air intake case 4 (see FIG. 8).

As is seen from FIG. 11, within the air inlet portion 502 of the casing501, there is installed a dust ionizing part 506 which includes aplurality of discharging plates 504 and a plurality of ionizing lines505. These plates 504 and lines 505 extend transverse to the inletportion 502 of the casing 501 and are arranged alternately, as shown.

As is understood from FIGS. 10 and 11, within a major portion of thecasing 501, there is installed a dust collecting part 513 whichcomprises a plurality of positive electrode plates 514 and a pluralityof negative electrode plates 517. These positive and negative electrodeplates 514 and 517 extend in parallel with the longitudinal axis of thecasing 501 and are arranged alternately.

As is seen from FIG. 10, each negative electrode plate 517 is formedwith two groups of ridges 516 and 516', one being raised in onedirection and the other being raised in the other direction. Theseridges 516 and 516' contact the neighboring positive electrode plates514 to define therebetween respective clearances in which the dusts inair are to be collected.

As is understood from FIGS. 11 and 12, these two groups of ridges 516and 516' are smoothly curved at their rear portions at generally rightangles toward the outlet portion 503 of the casing 501. With thesecurved ridges 516 and 516', the clearances defined between theneighboring positive and negative electrode plates 514 and 517 make upsmoothly curved guide ways for the air which travel therethrough. Theflow of air which is smoothly carried out in the guide ways is shown byarrows in FIGS. 11 and 12.

In this fifth embodiment 500, the air flow resistance is much reducedand a compact construction of the air collecting unit 509 is achieved.Furthermore, due to provision of the curved portions of the air guideways, the dust collecting efficiency of the electrostatic dustcollecting unit 509 is increased. That is, during flow in the air guideway, dusts in the air are forced to collide against the perpendicularlystanding walls of the positive and negative electrode plates 514 and517.

Referring to FIG. 13, there is shown an electrostatic dust collectingunit 609 which is employed in a sixth embodiment 600 of the presentinvention. Also this sixth embodiment 600 is a modification of theabove-mentioned fourth embodiment 400 of FIG. 8.

As is seen from the drawing, the electrostatic dust collecting unit 609comprises an elongate casing 601 constructed of electrically insulatingmaterial. The casing 601 is formed at longitudinally opposed ends withtwo air inlet portions 602 and 602' and at a middle portion with an airoutlet portion 603. Upon assembly of the air cleaning device 600, theair inlet portion 602 is directed toward the air inlet opening 3 (seeFIG. 3) of the cowl top 2 and the other air inlet portion 602' isdirected toward another air inlet opening (not shown) which is furtherformed in the cowl top 2. The air outlet portion 603 is directed towardthe air intake case 4 (see FIG. 8).

Within each air inlet portion 602 or 602' of the casing 601, there isinstalled a dust ionizing part 606 or 606' which includes a plurality ofdischarging plates 604 or 604' and a plurality of ionizing lines 605 or605'. These plates 604 or 604' and lines 605 or 605' extend transverseto the air inlet portion 602 or 602' and are arranged alternately, asshown.

Within a major portion of the casing 601, there is installed a ductcollecting part 613 which comprises a plurality of positive electrodeplates and a plurality of negative electrode plates. The positive andnegative electrode plates extend in parallel with one another betweenthe two dust ionizing parts 606 and 606' and are arranged alternately.

Similar to the case of the above-mentioned fifth embodiment 500, eachnegative electrode plate is formed with two groups of ridges 616 and616', one being raised in one direction and the other being raised inthe other direction. These ridges 616 and 616' contact the neighboringpositive electrode plates to define therebetween respective clearancesin which the dust in air are to be collected.

As is seen from the drawing, these two groups of ridges 616 and 616' aresmoothly curved and so shaped that the clearances defined between theneighboring positive and negative electrode plates make up two groups ofsymmetric air guide ways, each group extending from the correspondingdust ionizing part 604 or 604 toward the common air outlet portion 603.The flow of air which is smoothly carried out in the guide ways is shownby arrows in the drawing.

In this sixth embodiment, the air intake efficiency of the air cleaningdevice 600 is much increased as compared with the device 500 of thefifth embodiment.

Referring to FIG. 14, there is shown an electrostatic dust collectingunit 709 which is employed in a seventh embodiment 700 of the presentinvention. Also this seventh embodiment 700 is a modification of theabove-mentioned fourth embodiment 400 of FIG. 8.

As is seen from FIG. 14, the electrostatic dust collecting unit 709comprises an elongate casing 701 constructed of electrically insulatingmaterial. The casing 701 has an air inlet portion 702 which is to bedirected toward the air inlet opening 3 (see FIG. 8) of the cowl top 2and an air outlet portion 703 which is to be directed toward the airintake case 4 (see FIG. 8). Inner walls of the casing 701 which define adownstream portion of the interior of the casing 701 are smoothly curvedtoward the air outlet portion 703.

Within the air inlet portion 702 of the casing 701, there is installed adust ionizing part 706 which includes a plurality of discharging plates704 and a plurality of ionizing lines 705. These plates 704 and lines705 extend transverse to the inlet portion 702 of the casing 701 and arearranged alternately in a manner to define therebetween air guide ways,as shown.

Within a major portion of the casing 701, there is installed a dustcollecting part 712 which comprises a plurality of positive electrodeplates 713 and a plurality of negative electrode plates 714. Thesepositive and negative electrode plates 713 and 714 extend downward fromthe dust ionizing part 706 in parallel with the longitudinal axis of thecasing 701 and arranged alternately, as shown.

Each of the positive and negative electrode plates 713 and 714 has arear portion smoothly curved toward the air outlet portion 703 of thecasing 701. The outermost and innermost negative electrode plates 714are put on the smoothly curved inner walls of the casing 701.

Due to provision of the smoothly curved portions of the positive andnegative electrode plates 713 and 714 which are directed toward the airoutlet portion 703 of the casing 701, the air flow in the dustcollecting unit 700 is smoothed thereby reducing the air flow resistanceof the unit 700. Furthermore, due to provision of such smoothly curvedportions of the positive and negative electrode plates 713 and 714, thedust collecting effeciency of the electrostatic dust collecting unit 709for the same reason as is mentioned in the part of the fifth embodiment.

Referring to FIG. 15, there is shown an electrostatic dust collectingunit 809 which is employed in an eighth embodiment 800 of the presentinvention.

The electrostatic dust collecting unit 809 comprises an elongate casing801 constructed of electrically insulating material. The casing 801 isformed at longitudinally opposed ends with two air inlet portions 802and 802' and at a middle portion with an air outlet portion 803. Uponassembly of the air cleaning device 800, the air inlet portion 802 isdirected toward the air inlet opening 3 (see FIG. 3) of the cowl top 2and the other air inlet portion 802' is directed toward another airinlet opening (not shown) which is further formed in the cowl top 2. Theair outlet portion 803 is directed toward the air intake case (see FIG.8).

Within each air inlet portion 802 or 802' of the casing 801, there isinstalled an ionizing part 806 or 806' which includes a plurality ofdischarging plates 804 or 804' and a plurality of ionizing lines 805 or805'. These plates 804 or 804' and lines 805 or 805' extend transverseto the air inlet portion 802 or 802' and are arranged alternately asshown.

Within a major portion of the casing 801, there is installed a dustcollecting part 812 which comprises a plurality of positive electrodeplates 813 and 813' and a plurality of negative electrode plates 814 and814'. As shown, these electrode plates 813, 813', 814 and 814' aregrouped into two, one being the group which consists of the electrodeplates 813 and 814 extending from the dust ionizing part 806 to the airoutlet portion 803 of the casing 801 and the other being the group whichconsists of the electrode plates 813' and 814' extending from the dustionizing part 806' to the air outlet portion 803. The positive andnegative electrode plates 813 and 814 (or, 813' and 814') extend inparallel with one another and with the longitudinal axis of the case 801and are arranged alternately.

As shown, the positive and negative electrode plates of each group hasrear portions smoothly curved toward the air outlet portion 803 of thecasing 801. The outermost and innermost negative electrode plates 814and 814' are put on inner walls of the casing 801.

In this eighth embodiment, the air intake efficiency of the air cleaningdevice 800 is much increased as compared with the device 700 of theseventh embodiment.

Referring to FIGS. 16 to 18, there is shown an air cleaning device 900of a ninth embodiment of the present invention.

As is seen from FIGS. 16 and 17, the air cleaning device 900 of thisembodiment comprises an air box 916 which is mounted beneath a cowl top918 of a motor vehicle "V". As is seen from FIG. 16, the air box 916extends transversely at a rear portion of an engine room of the vehicle"V". Denoted by numeral 914 is a hood for the engine room and denoted bynumeral 917 is a windshield of the vehicle "V".

Denoted by numerals 911 and 911' are hood ridge reinforcing hollowedstructures which extend along side walls of the engine room.

As is seen from FIG. 18, each reinforcing hollowed structure 911' or 911is constructed by securing a separate elongate channel member 930 to afront fender 913 of the vehicle "V". Denoted by numeral 912 is a frontleft tire (as viewed by a driver) and denoted by 915 is a sidereinforcing member which is secured to an inner wall of the front fender913.

As is seen from FIGS. 16 and 17, the transversely elongated air box 916has both ends which are opened and mated with openings 919 and 919'formed in the respective reinforcing hollowed structures 911 and 911'.Each hollowed structure 911 or 911' has an open front end covered with ametal mesh 922 or 922'. Thus, the interior of the air box 916 iscommunicated with the atmosphere through two air intake ways, oneincluding the opening 919, the interior of the hollowed structure 911and the front open end 922, and the other including the opening 919',the interior of the hollowed structure 911' and the front open end 922'.

As is seen from FIG. 17, within the air box 916, there is provided anair filter holder 912 which is mounted above an opening 908 formed in alower wall of the air box 916. The air filter holder 12 has an upperopen side on which a pleated paper filter 906 is mounted.

An air intake case 904 is connected to the lower wall of the air box 916to communicate with the opening 908. The air intake case 904 is led to apassenger compartment P of the vehicle through suitable air guide ductsD. An electric air blower 907 is installed in the air intake case 904.

As is seen from FIG. 17, each of the reinforcing hollowed structures 911or 911' is formed at a lower portion with a water draining opening 921or 921' through which foreign water is to be discharged to the outside.In order to prevent such foreign water from entering the air box 916,water stoppers 920 and 920' are provided by inner walls of thereinforcing hollowed structures 911 and 911'. In fact, when the vehicle"V" is being washed, water tends to enter the hollowed structures 911and 911' from the front open ends.

When, in operation, the electric air blower 907 is energized, theatmospheric air is fed to the air box 916 through the two air intakeways. This means a marked reduction in air flow resistance of the aircleaning device 900. Thus, a satisfied amount of fresh air can be givento the passenger compartment.

Referring to FIGS. 19 to 21, there is shown an air cleaning device 1000of a tenth embodiment of the present invention.

Since this tenth embodiment 1000 is similar to the above-mentioned ninthembodiment 900, only parts and constructions which are different fromthose of the ninth embodiment will be described and the same parts asthose of the ninth embodiment 900 will be noted by the same numerals.

As is seen from FIG. 19, in this tenth embodiment 1000, an additionalopening 1023 or 1023' is formed in a front portion of each reinforcinghollowed structure 911 or 911' for the purpose of water draining. As isseen from FIG. 20, the opening 1023 or 1023' is provided by pressing outand raising a part 1024 of a lower wall "L" of the structure 911 or911'. The raised part 1024 extends from a rear end of the opening 1023or 1023'.

Furthermore, as is seen from FIG. 21, the drain opening 921 or 921'formed in each reinforcing hollowed structure 911 or 911' has a bottomwhich is lower than the lower wall "L" of the structure 911 or 911'.Denoted by numerals 1026 and 1026' are apertured panels which are fixedto the longitudinal both ends of the elongated air box 916.

Due to provision of the two uniquely shaped openings 921 and 1023 (or,912' and 1023') in each reinforcing hollowed structure 911 or 911', thewater draining from the structure 911 or 911' is much effectivelycarried out.

Referring to FIGS. 22 and 23, there is shown an air cleaning device 1100which is an eleventh embodiment of the present invention.

Since this embodiment is similar to the above-mentioned ninth embodiment900, only parts and constructions which are different from those of theninth embodiment will be described and the same parts as those of theninth embodiment 900 will be denoted by the same numerals.

As is seen from FIG. 23, in this eleventh embodiment 1100, anelectrostatic dust collecting unit 1129 is installed in the air box 916.The dust collecting unit 1129 comprises an elongate casing, two dustionizing parts 1127 and 1127' installed in longitudinal open ends of thecasing and a dust collecting part 1128 installed in a major portion ofthe casing.

The dust ionizing parts 1127 and 1127' are directed toward the openings919 and 919' of the reinforcing hollowed structures 911 and 911'.

The dust collecting unit 1129 may be the type of the afore-mentionedunit 600 of FIG. 13 or the unit 800 of FIG. 16.

An air outlet portion of the dust collecting unit 1129 is disposed on afilter holder 912 by which a charcoal filter 1130 is held. An air intakecase 904 and an electric air blower 907 are connected to the air box 916in the same manner as the afore-mentioned ninth embodiment.

In this eleventh embodiment 1100, the following advantages are obtained.

Due to usage of the two air induction passages 911 and 911', satisfiedamount of fresh air can be given to the passenger compartment P.

Due to usage of the electrostatic dust collecting unit 1129, very fineparticles can be removed from the air fed to the passenger compartmentP.

Due to usage of the charcoal filter 1130, bad smell can be removed fromthe air fed to the passenger compartment.

Referring to FIGS. 24 to 28, particularly FIGS. 24 to 26, there is shownan air cleaning device 1200 which is a twelfth embodiment of the presentinvention.

As will become apparent as the description proceeds, in this twelfthembodiment, an inspection aperture, which is usually covered with a lid,is formed in a cowl top structure for facilitating inspection of an airfilter installed in an air box.

In FIG. 25, there is shown a cowl top structure to which the twelfthembodiment 1200 of the present invention is practically applied. Denotedby numeral 40 is a windshield of a motor vehicle which is denoted byreference "V" in FIG. 24. Denoted by numeral 45 in FIG. 25 is a hood foran engine room. When the hood 45 is properly put on the engine room, arubber seal is compressed for achieving a sealing therebetween.

As is best shown in FIG. 25, the cowl top structure comprises a cowl toppanel 50 which extends transversely at a rear portion of the engineroom. The cowl top panel 50 includes a transversely extending front part50a which faces the engine room and a transversely extending upper part50b which faces upward. A transversely extending dash upper panel 60 issecured to the cowl top panel 50 to constitute an air box 70 as shown.Although not shown in the drawings, an air intake opening is provided inthe upper part 50b of the cowl top panel 50 to establish a communicationbetween the surrounding air and the interior of the air box 70.

The upper part 50b of the cowl top panel 50 is formed with a rectangularopening 52. The opening 52 is surrounded by a rectangular gutter 53defined by the upper part 50b. The rectangular opening 52 is covered bya rectangular cowl top cover 54 (see FIG. 26) which is secured to theupper part 50b of the cowl top panel 50 by means of bolts or the like.The cowl top cover 54 is formed with a rectangular wall 51 whichprojects into the gutter 53 to serve as a water stopper. The cowl topcover 54 may be constructed of a plastic. For achieving a watertightsealing, a seal member 55 is disposed between a raised peripheral edgeof the opening 52 and the cover 54.

Within the air box 70, there is installed an air filter holder 62 whichis secured to the dash upper panel 60. A pleated paper filter 61 is heldby the air filter holder 62. The dash upper panel 60 is formed below thefilter 61 with an opening 64 which is exposed to an air intake case 65.Although not shown in the drawing, an electric air blower is installedin the air intake case 65 to enforcedly carry filtered atmospheric airinto the passenger compartment P through air guide ducts like in thecase of the above-mentioned embodiments.

As is seen from FIG. 26, the rectangular cowl top cover 54 is formedwith a rectangular inspection aperture 56 which is rimmed by arectangular bank 57. The inspection aperture 56 is so sized as to permitinsertion of hands of an operator. On and around the rectangular bank57, there extends a ridge 58 which has a generally triangular crosssection as shown in FIG. 27. Preferably, the inspection aperture 56 ispositioned just above the air filter 61 for ease with which the airfilter 61 is handled by an operator.

As is seen from FIG. 26, a rectangular lid 80 is secured through bolts81 to the cowl top cover 54 to sealingly cover the inspection aperture56. Denoted by numeral 83 is a seal bush which is to be compressedbetween the cowl top cover 54 and the lid 80.

The lid 80 has a rectangular bank portion 82 which is sized and shapedto mate with the bank 57 of the inspection aperture 56.

As is seen from FIG. 25, the lid 80 is formed at its depressed innerwall with a rectangular groove 84. Upon assembly of the lid 80, theridge 58 of the inspection aperture 56 is intimately put into the groove84 to achieve a tight connection between the cowl top cover 54 and thelid 80. As is seen from FIG. 27, a seal member 86, such as polyurethanefoam or the like, is disposed between the ridge 58 and the groove 84.

FIGS. 27 and 28 show methods for securing the lid 80 to the cowl topcover 54 by using the bolts 81. In the method of FIG. 27, the cowl topcover 54 is formed with threaded openings 59 into which the bolts 81 arescrewed. In the method of FIG. 28, nuts 90 are used which are fixed to aback surface of the cowl top cover 54 by means of flanges 92 which aredefined by the cowl top cover 54. The bolts 81 are engaged with the nuts90, as shown.

Usually, the rectangular lid 80 is secured to the cowl top cover 54 toblock up the inspection aperture 56. Thus, when, in operation, theelectric air blower (not shown) installed in the air intake case 65 (seeFIG. 25) is energized, atmospheric air is led into the air box 70through the air intake opening (not shown), then cleaned by the airfilter 61 and then fed to the passenger compartment P through the airguide ducts (not shown), like in the above-mentioned embodiments.

While, when inspection of the air filter 61 becomes necessary, the lid80 is removed by loosening the bolts 81. With this, an operator caneasily inspect and handle the air filter 61 through the inspectionaperture 56.

What is claimed is:
 1. An air cleaning system for use in a motor vehiclehaving a cowl top and a passenger compartment, comprising:a firststructure secured to said cowl top to provide an air box; a secondstructure secured to said first structure to provide an air intake case;first means for defining in said cowl top a first opening through whichthe interior of said air box and the surrounding air are communicated;second means for defining a second opening through which the interior ofsaid air box and that of said air intake case are communicated; thirdmeans for fluidly communicating the interior of said air intake casewith said passenger compartment; an air filter unit located in said airbox upstream of said second opening so that air in the air box isfiltered by said air filter unit upon flowing from the air box to theair intake case through said second opening; said air filter unitincluding an air filter holder and an air filter element held by saidholder; an electric air blower positioned in said air intake case for,which upon energization thereof, generates an air flow from said firstopening to said passenger compartment through the interior of said airbox, said air filter unit, said second opening, the interior of said airintake case and said third means; bypass means for producing a bypasspassage between the interior of said air box and that of said air intakecase bypassing said air filter element when said air filter element isblocked with arrested dusts by a certain degree, said bypass meansincluding means defining, in said air filter holder, at a portiondownstream of said air filter element, a third opening through which theinterior of said air box and that of said air intake case are freelycommunicated, a damper door pivotally connected to an inner wall of saidair filter holder in a manner to selectively open and close said thirdopening from the back side, and biasing means for biasing said damperdoor in a direction to close said third opening, said biasing meanscomprising a spring which permits said damper door to open said thirdopening when the pressure in the air filter holder downstream of saidair filter element is reduced to a certain level; means for defining insaid air intake case a fourth opening; passage means for communicatingsaid fourth opening and said passenger compartment; and a switch doorpivotally connected to said air intake case to selectively open andclose said fourth opening and said second opening.
 2. An air cleaningsystem for use in a motor vehicle having a cowl top and a passengercompartment, comprising:a first structure secured to said cowl top toprovide an air box; a second structure secured to said first structureto provide an air intake case; first means for defining in said cowl topa first opening through which the interior of said air box and thesurrounding air are communicated; second means for defining a secondopening through which the interior of said air box and that of said airintake case are communicated; third means for fluidly communicating theinterior of said air intake case with said passenger compartment; meansfor defining in said air intake case a fourth opening; passage means forcommunicating said fourth opening and said passenger compartment; aswitch door pivotally connected to said air intake case to selectivelyopen and close said fourth opening and said second opening; an airfilter unit located in said air box upstream of said second opening sothat air in the air box is filtered by said air filter unit upon flowingfrom the air box to the air intake case through said second opening,said air filter unit including an air filter holder and an air filterelement held by said holder, said holder further including at a portiondownstream of said air filter element, means defining a third openingthrough which the interior of said air box and that of said air intakecase are freely communicated; an electric air blower positioned in saidair intake case for, upon energization thereof, generating air flow fromsaid first opening to said passenger compartment through the interior ofsaid air box, said air filter unit, said second opening, the interior ofsaid air intake case and said third means; and bypass means forproducing a bypass passage between the interior of said air box and thatof said air intake case bypassing said air filter element when said airfilter element is blocked with arrested dust by a certain degree, saidbypass means including a damper door pivotally connected to an innerwall of said air filter holder in a manner to selectively open and closesaid third opening from the back side, and a biasing spring for biasingsaid damper door in a direction to close said third opening, saidbiasing spring permitting said damper door to open said third openingwhen the pressure in the air filter holder downstream of said air filterelement is reduced to a certain level.
 3. An air cleaning system asclaimed in claim 2, further comprising an actuator which drives saidswitch door upon energization thereof.
 4. An air cleaning system asclaimed in claim 3, further comprising a cam member which is installedin said air filter holder, said cam member being connected with one endof said spring to induce a snap action movement of said damper door. 5.An air cleaning system as claimed in claim 4, further comprising aswitch which is installed in said air filter holder to sense the openand close conditions of said damper door, said switch controlling saidactuator in response to the open and close conditions of said damperdoor.
 6. An air cleaning system as claimed in claim 5, in which uponsensing the open condition of said damper door, said switch operatessaid actuator in such a manner that said switch door closes said secondopening while opening said fourth opening.
 7. An air cleaning system asclaimed in claim 6, further comprising:means for defining in said airintake case a fifth opening; passage means which extends from said fifthopening to demister nozzles which face a windshield of said motorvehicle; and an air cooling unit installed in said passage means.
 8. Anair cleaning system as claimed in claim 7, further comprising a controlcircuit, said control circuit energizing said air cooling unit to coolthe air in said passage means when said switch senses the open conditionof said damper door.
 9. An air cleaning system as claimed in claim 2, inwhich said air filter holder has an inclined open upper side on whichsaid air filter element is mounted, said open upper side being inclinedtoward said first opening.
 10. An air cleaning system as claimed inclaim 2, wherein said air filter holder has an inclined open upper sideon which said air filter element is mounted.